Embarking on a Journey: The Life Cycle of Water Scorpions

Water scorpions can be found in various aquatic habitats, and they are fascinating creatures with distinct life cycles. You might be surprised to learn that water scorpions in the genus Ranatra resemble underwater walking sticks, using their mantis-like forelegs to capture small aquatic prey source.

In this article, we’ll delve into the life cycle of water scorpions, which goes through several stages, including egg-laying, nymph development, and adulthood. Bearing in mind the importance of understanding these unique insects, you will gain a deeper appreciation for their role in our ecosystem as they strive to survive and reproduce in their watery habitats.

Water Scorpion Overview

Water scorpions are fascinating aquatic insects belonging to the Nepidae family, which is a part of the larger order Hemiptera, also known as true bugs. They resemble underwater walking sticks and are sometimes mistaken for actual scorpions due to their similar appearance.

These creatures can be found in North America and in other regions worldwide. The most common water scorpion genus in North America is Ranatra, while in Asia, Laccotrephes japonensis is the most prevalent. There are also other genera, like Nepa, which are characterized by their fat bodies.

Water scorpions are well-adapted to their aquatic environment. Some of their distinguishing features include:

  • Long, slender body
  • Three pairs of jointed legs
  • Mantis-like grasping forelegs for capturing prey
  • Needle-like appendage at the tip of their abdomen

The needle-like appendage is actually a breathing tube, which they use to take in air from the water surface while remaining submerged. It allows them to be efficient predators, preying on small aquatic creatures like mayfly nymphs.

As for their life cycle, water scorpions undergo simple or incomplete metamorphosis. This means they do not go through a larval or pupal stage, like some other insects. Instead, they hatch from eggs directly into smaller versions of their adult selves, called nymphs, and grow through a series of molts until reaching adulthood.

Now that you have a basic understanding of water scorpions, here’s a quick comparison between the most common genera mentioned earlier:

Genus Appearance Distribution
Ranatra Thin-bodied, long-legged North America
Nepa Fat-bodied, short-legged North America
Laccotrephes japonensis Slender with elongated rostrum Asia

In conclusion, water scorpions are intriguing aquatic insects with a unique morphology and lifestyle. Although they may look fearsome, they pose no threat to humans and are an essential part of aquatic ecosystems.

Physical Characteristics

Water scorpions, such as Nepa apiculata, are unique aquatic insects with interesting physical features that set them apart from other creatures. In this section, we’ll explore some of these characteristics to help you better understand their appearance and functionality.

Your first encounter with a water scorpion may be surprising, as their appearance is quite distinctive. They range in length from 0.8 to 1.2 inches, making them relatively small but noticeable creatures when spotted in their aquatic environment. Their size is coupled with a slender, elongated body that resembles an underwater walking stick1.

Regarding their wings, you’ll find that water scorpions possess a set of functional wings, allowing them to fly short distances when necessary. This attribute enables these insects to move about in search of new habitats or food sources.

A crucial aspect of their physical structure is the tail. Instead of a traditional tail, water scorpions have a slender, needle-like appendage at the tip of their abdomen1. This structure serves as a breathing siphon, which helps them to take in oxygen from the water while remaining submerged.

One of the distinguishing features of water scorpions is their thorax, which houses specialized forelegs. These forelegs are raptorial, or mantis-like, and are employed by the insect for grasping and seizing small aquatic prey1. While you might initially mistake them for antennae, they are actually an essential part of the water scorpion’s hunting apparatus.

To summarize, water scorpions exhibit several fascinating physical characteristics:

  • Length: 0.8 to 1.2 inches
  • Slender, elongated body
  • Functional wings for short-distance flight
  • Needle-like appendage serving as a breathing siphon
  • Raptorial forelegs for grasping and seizing prey

Understanding these traits will give you a clearer insight into the captivating world of water scorpions and their life cycle.

Habitat and Distribution

Water scorpions can be found in various freshwater habitats. They typically prefer locations with slow-moving or stagnant water, such as ponds, streams, and ditches.

In these environments, you might find them in:

  • Lakes with muddy bottoms
  • Overwintering sites like temporary wetlands
  • Rice paddy systems and rice fields
  • Weed-covered ridges near irrigation ponds

Their versatility allows them to adapt to a range of environments, including agricultural areas with rice fields, where they can be found making use of the rice paddy system and irrigation ponds.

Water scorpions are not only limited to natural habitats; they can also be found in man-made locations, such as rice fields and irrigation ponds. This adaptability allows them to thrive in various ecosystems, providing ample sources of food and shelter.

So, when you come across slow-moving freshwater bodies like ponds or streams with rich aquatic vegetation, keep an eye out for these fascinating creatures!

Life Cycle

Water scorpions have an interesting life cycle that begins with eggs. The female deposits her eggs on submerged vegetation or other underwater structures. Once the eggs hatch, the young water scorpions, called nymphs, emerge and start to grow.

These nymphs undergo incomplete metamorphosis, which means they gradually grow larger and more developed without drastic changes in form. They typically progress through several stages, gradually transforming into adults.

As an adult, a water scorpion is a predatory insect that uses its elongated breathing tube to ambush and capture prey. They prefer still or slow waters with detritus and muddy bottoms, hiding among plant stalks and submerged vegetation.

Regarding reproduction, adult water scorpions mate and lay eggs in springtime, starting the cycle anew. Some water scorpions may overwinter as adults, remaining inactive during the colder months and resuming activity once the weather warms up.

To recap, the key points in the water scorpion life cycle are:

  • Starts as eggs laid on submerged vegetation
  • Nymphs emerge and grow through incomplete metamorphosis
  • Adults are ambush predators in calm waters
  • Reproduction occurs in spring
  • Some adults overwinter in an inactive state

By understanding their life cycle, you can better appreciate the fascinating world of water scorpions and their unique adaptations for survival.

Feeding and Prey

Water scorpions primarily feed on small aquatic organisms. They are opportunistic predators, meaning they will eat whatever they can find and catch. In their natural habitat, you’ll find water scorpions feasting on a variety of aquatic invertebrates.

Their diet typically consists of tadpoles, small fish, aquatic insects, and mosquito larvae. To feed, they use their raptorial forelegs to seize their prey, providing them with a steady supply of food. For example, if you observe a water scorpion hunting, you might witness it catching fish or snatching a mosquito larva.

In comparison to other aquatic predators, water scorpions are relatively small but still quite effective. They are not known for being picky eaters and will adapt their feeding habits based on the availability of prey.

Here are some common prey items for water scorpions:

  • Tadpoles
  • Small fish
  • Aquatic insects
  • Aquatic invertebrates
  • Mosquito larvae

Remember that as a water scorpion’s environment changes, so will its choice of prey. As long as there are small aquatic creatures available, a water scorpion will never go hungry.

Behavior

Water scorpions are fascinating creatures with unique behaviors. For instance, they are known for their ability to swim and ambush their prey, such as small aquatic insects and tadpoles. They mainly rely on their camouflage and stealth to catch their prey1.

Water scorpions are also capable predators. They use their elongated, snorkel-like breathing tube to take in air while staying submerged in water2. This special adaptation helps them maintain a low profile while hunting. Here are some key features of water scorpions:

  • Swim efficiently in water
  • Ambush their prey using camouflage
  • Use a snorkel-like breathing tube for respiration

When it comes to seeking shelter and securing their survival, water scorpions rely on various tactics. They are known to inhabit aquatic habitats that provide cover, such as submerged vegetation and debris3. These environments not only offer refuge from predators but also enhance their hunting techniques.

Survival rates of water scorpions may be studied using methods like mark and recapture censuses, Jolly-Seber method, survival analysis, and recapture rate. These techniques help researchers to better understand water scorpions’ population dynamics, migration patterns, and population size4.

In conclusion, water scorpions exhibit intriguing behaviors that make them exceptional predators and survivors in their aquatic habitats. Understanding their behavior and how they thrive in their environment is crucial for their conservation and management.

Conservation Status

Water scorpions play an important role in aquatic ecosystems, especially in terms of biodiversity conservation. Their presence can be an indicator of healthy and diverse wetland habitats. However, as with many other aquatic species, various factors can impact their conservation status and abundance.

The diversity of water scorpions can be affected by different worldwide environmental factors, including habitat loss and pollution. In some cases, water scorpions may face challenges similar to their distant cousins, the true scorpions. For example, when specific vegetation types they rely on are threatened, their populations might decline as well.

As a comparison, consider the endangered giant water bug and the endangered water bug, which are also sensitive to changes in their environment. These bugs could end up on the red data list, just like many other aquatic species at risk. While there’s currently no clear indication that water scorpions share a similar status, it’s crucial to monitor their populations and maintain healthy wetland habitats.

To maintain water scorpion populations and reduce the risk of declining abundance, consider supporting alternative wetlands and promoting sustainable land use practices. By protecting their habitats, you can help ensure the conservation of not just water scorpions but countless other species that rely on aquatic ecosystems as well.

Water Scorpions and Human Interaction

You might encounter water scorpions in various aquatic habitats. There are about 13 species in North America and 270 species worldwide, which belong to the family Nepidae. Some broader-bodied species like the Brown Water Scorpion (Ranatra fusca) even resemble the appearance of a giant water bug.

These invertebrates are a fascinating part of aquatic fauna, but can also be a concern in some areas. For example, they might appear in regions like Hyogo and Central Japan, where rice saplings are drained and irrigated in ploughed fields.

With their unique and diverse characteristics, you might be wondering how they interact with humans. Let’s discuss two main aspects to consider when encountering them:

  • Sting: Despite their name, water scorpions don’t possess a sting like true scorpions. Instead, they have a needle-like appendage at the end of their abdomen that they use for respiration.
  • Bite: Although they don’t sting, water scorpions can bite if you try to handle them. Their bite is not dangerous, but it can be painful. It’s best to observe these fascinating creatures from a safe distance.

In terms of pest control, water scorpions are unlikely to pose a significant threat to crops or humans. They mainly feed on small aquatic prey and help to maintain a balanced ecosystem in water bodies.

Overall, water scorpions are intriguing creatures with a unique distribution and role in aquatic ecosystems. It’s essential to appreciate and respect their role in nature and interact with them cautiously.

Footnotes

  1. Water Scorpions | Missouri Department of Conservation 2 3 4
  2. Oklahoma State University – OSU Extension
  3. U.S. Fish & Wildlife Service
  4. Armed stem to stinger: a review of the ecological roles of scorpion

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Water Scorpions in Public Pool

 

Water Scorpion
Location:  Swimming pool in Tucson AZ
August 1, 2010 10:53 pm
Hello, I believe this is a water scorpion (actually 2) that were found in a public swimming pool today (early August) in Tucson AZ. It is about 2 inches long, abit longer if you measure the tail like appendage. Water bugs are not uncommon this time of year, but this variety was new to me. I identified it as a water scorpion from other posts on your site. How do water bugs survive in swimming pools when the chemicals that make the water safe for swimming are supposed to destroy organic matter?
Thanks! Teri

Water Scorpions

Hi Teri,
You are correct.  These are Water Scorpions.  Water Scorpions and most other adult aquatic insects breath air, in the case of the Water Scorpion, through the breathing tube at the end of the abdomen which functions like a snorkel.  Since they do not take oxygen from the water, they are not adversely affected by the chlorine in the way that fish with gills may die in chlorinated water.  If conditions become unbearable, the Water Scorpions just take flight and find a better habitat.

Letter 2 – Water Scorpion from Gambia

 

Big Gambian water loving bug
March 29, 2010
Hi Bug peeps, recently got married in the gambia, west africa and stayed with my mum. She often gets these huge bugs in her pool – they are about 6″ including the long tail, and when they are fished out and dried off, their underbellies are bright orange. Any ideas what they might be? I’m guessing that’s not a sting… I hope!
Alison, UK
Gambia, west africa

Water Scorpion

Greetings Alison,
This is an impressive Water Scorpion, and though the name might imply a stinger, you are correct that it is not a stinger.  The Water Scorpion breathes through that extremity, using it like a snorkel.  Water Scorpions are quite capable of producing a painful bite if they are carelessly handled, but the bite comes from its piercing beak, the means by which it sucks nourishment from any prey it captures with is raptorial front legs.

Wow, thanks Daniel!
They always seem pretty chilled out, they never try to bite –  they just have a swim, then dry off to fly off in a swirl of neon orange – they lumber along the ground but they are graceful otherwise.
I’ll let Mum know, she could not remember what the local name for them was but she’ll be glad to know what they are.
Very much appreciated!
Alison

Letter 3 – Water Scorpions Mating

 

Toe Biters??
Hi there,
I live in Sydney Australia and found your website when trying to identify these bugs, found in our backyard swimming pool. I think they might be what you call Toe-biters or Giant Water Bugs, but these ones have longer front appendages and long spikes at the back, at least the length of their abdomen. There is one smaller one on the back of the larger one and does not get off. Are they mating or is the little one eating the big one? Please help, my girls are too scared to go back in the pool!!!!
Janine in Oz

Hi Janine,
My Oh My we are thrilled to have received your excellent photo. We haven’t posted anything on our Bug Love page in weeks. These are actually Water Scorpions, relatives of Toe Biters that can also deliver a painful bite. They are mating. Tell your girls not to fear the water. The Water Scorpions are probably not established in your pool unless the water is stagnant. The appendages are actually breathing aparati, similar to snorkles.

Letter 4 – Water Scorpions

 

water scorpion?
I found what I thought was a dead walking stick in my pond in Myakka City, Florida. Surprise it was alive and there were two of them. Are these water scorpions? Do they really bite? They didn’t seem very aggresive when I touched their front legs.
Lis

Hi Lis,
These surely are Water Scorpions in the genus Ranatra, and they really will give a painful bite. Your photo is totally awesome.

Letter 5 – Water Scorpion pummelled to death

 

What is this thing?
Wed, Dec 31, 2008 at 7:26 AM
Found this bug by the open overhead door at the metal shop I was working in. It was September I believe. I kept it alive and scooped him up with a piece of paper and took it outside, however the owners son proceeded to smash it repeatedly with a 5 lb dead blow hammer, of course I was wroth with him for it. He smashes all the weird bugs that seem to show up in large numbers around the shop also. Found a luna moth that had been knocked down by a robin, and I saved a praying mantis that was over 4 inches long this fall! Don’t know what this thing is, had small hooks on the end of it’s strange mantis like front legs. Some damage to it in the picture, probably as a result of flying into the stockroom of a metal shop! if you could identify it, I would be grateful.
Matt
Western NY state, USA

Water Scorpion smashed to death
Water Scorpion smashed to death

Hi Matt,
We are very sorry to hear that this unfortunate Water Scorpion has been pummelled to death by an insensitive insect hater.  The Water Scorpion in the genus Ranatra is a predatory aquatic insect that can fly and is sometimes attracted to lights.  Water Scorpions get their name from the painful bite they will deliver if they are mishandled, but the species does not aggressively bite humans.

Letter 6 – Water Scorpions eat Damselfly Naiad

 

water scorpions share meal
Tue, Jan 6, 2009 at 10:49 AM
Hi,
I thought you guys might like this picture I took last year. Over the summer I raised several water scorpions, and these are two of them. They were both eating the same damselfly larva at the same time. I thought that this was a rare moment and snapped several shots. I later realized that the darker one had little egg pouches, or mites of some kind on one of its legs, and that there is another damselfly larva on the lighter one’s back. I hope you guys enjoy this image. Thanks again for the awesome site.
Josh Kouri
Oklahoma

Water Scorpions eat Damselfly Naiad
Water Scorpions eat Damselfly Naiad

Hi again Josh,
Thanks for the interesting image of two Water Scorpions feeding on a Damselfly Naiad.  It will be an excellent addition to our Food Chain section.  We took the liberty of adding Oklahoma to your posting as you did not submit your letter using our new form that requires a location.  Adding the location requirement to our online form has saved us the bother of writing back for a location.  Please include a location in any future letters.

Letter 7 – Water Scorpion from Gambia

 

Subject: unknown creature
Location: Kotu beach, Gambia
August 1, 2012 1:15 pm
Saw this insect? on the beach in the Gambia.It was around 25-30 cm long.Very big !Can you help?
Signature: anyway

Water Scorpion

Dear anyway,
This is an aquatic True Bug known as a Water Scorpion.  Though they are not considered venomous, they are predators with piercing and sucking mouthparts that can deliver a painful bite if they are carelessly handled or accidentally encountered in the water.  Most Water Scorpions can also take flight in the event their aquatic homes dry out.

Letter 8 – Water Scorpion from Thailand

 

Subject: Bug discovered in Koh Phangan
Location: Chaloklum, Koh Phangan, Thailand
May 2, 2013 8:52 am
Found this bug next to the pool, it was not frightened of water and used its two back legs to rub the water off its back. The two large pincers at the front were also used for walking.
Signature: Emma and Maz

Water Scorpion
Water Scorpion

Dear Emma and Maz,
We are thrilled to post your photo because we haven’t received an identification request for a Water Scorpion in quite some time.  Water Scorpions are aquatic True Bugs that reportedly have a very painful bite.

Letter 9 – Water Scorpion from Thailand

 

Subject:  This was found at the pool, straightened up into a twig when removed.
Geographic location of the bug:  Chiangmai, Thailand
Date: 11/03/2017
Time: 11:25 PM EDT
Can you tell me what this guy is?
How you want your letter signed:  Richard

Water Scorpion

Dear Richard,
This is an aquatic, predatory True Bug commonly called a Water Scorpion.  They are reported to have a painful bite.

Letter 10 – Water Scorpion from Thailand

 

Subject:  odd creature found in Thailand
Geographic location of the bug:  Bangkok suburbs, Thailand
Date: 09/01/2018
Time: 12:45 AM EDT
Your letter to the bugman:  This thing was in a swimming pool. Didn’t look to be struggling. I took it out and it sat on the side of the pool. I took some photos and a few minutes later I couldn’t find it. As you can see it has 4 legs, no wings, two large eyes and quite a long tail.
How you want your letter signed:  Alex Slater

Water Scorpion

Dear Alex,
This is a predatory Water Scorpion, and the common name is a reference to its painful bite.  Water Scorpions are also capable of flying.

Letter 11 – Water Scorpion from Vietnam

 

Subject:  Unknown bug
Geographic location of the bug:  Vietnam, Ho Chi Minh, Masteri
Date: 03/30/2019
Time: 11:10 AM EDT
Your letter to the bugman:  The bug is brown with no wings. It is very strong as it is still stuck to my net when I shakes it really hard.
How you want your letter signed:  Allison

Water Scorpion

Dear Allison,
This looks to us like an aquatic, predatory Water Scorpion.  You did not indicate if you were using your net in the water or to catch flying things.  Water Scorpions actually do have wings and they are capable of flying from pond to pond.  Handle Water Scorpions with caution.  They can bite and the bite is reported to be quite painful.

Authors

    by
  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

4 thoughts on “Embarking on a Journey: The Life Cycle of Water Scorpions”

  1. Why do I get water scorpions? Do they sting humans? I’ve upped my chlorine. What bugs do they sting/eat? I live next to BLM land in gold canyon az and do get interesting bugs at my pool.

    Reply
    • Water Scorpions might bite, but they do not sting. They eat aquatic insects and other small invertebrates and vertebrates. We don’t know why they are attracted to your pool.

      Reply
  2. Tucson Az,I have at least one in my pool this year. First I’ve seen had to look it up hence why I landed here. Usually have I guess regular water bugs time to time? I let my pool go wild in the winter then aggressively treat it once the mosquito larvae show up. It’s lousy with chems right now including mosquito death doughnuts and this bug seems to be fine. It ended up in my filter basket and I tossed it back in, perhaps my water spiders will enjoy it. Curious how it got there in the first place. I’m guessing it can fly? But how far? Once the pool is clear the chems go away and the solar copper ionizer thing I built takes over. Hope it does well and doesn’t bother anyone.

    Reply

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